Autoři popsali případ 64-letého muže, u kterého byla zjištěna chronická lymfatické leukémie (CLL) před pěti lety. V současné době byl pacient přijat pro nádor kůže v lumbální oblasti vlevo. Histologické a imunohistologické vyšetření ukázalo, že jde o karcinom z Merkelových buněk (MCC). Elektronově mikroskopické vyšetření ukázalo charakteristické paranukleární globule tvořené intermediálními filamenty. Koincidence MCC a CLL je poměrně vzácná a cytogenetická vyšetření zde nebyla publikována. Vyšetřovali jsme RB1 gen pomocí interfázové FISH metody. Cytogenetické vyšetření RB1 genu ukázalo bialelickou deleci u nádorových buněk CLL; u MCC byla bialelická delece u 33 % a monoalelická delece u 57 % buněk. Současně byla prokázána trizomie 6 a delece 1p36. Vyšetření nenádorové kůže ukázalo přítomnost RB1 genu v obou alelách. Podle literárních údajů má vyšetření RB1 genu u CLL význam při stanovení prognózy onemocnění. Vztah mezi delecí RB1 genu a prognózou onemocnění nebyl dosud u MCC stanoven a vyžaduje vyšetření dalších případů.

The authors report a case of a 64-year-old man with chronic lymphocytic leukaemia (CLL) diagnosed 5 years ago. Recently, the patient was admitted with a tumour of the skin in the left lumbar region. Histological and immunohistochemical examinations established the diagnosis of Merkel cell carcinoma (MCC). Electron-microscopic examination revealed the formation of spherical aggregates of intermediate-sized filaments in the perinuclear region. The coincidence of MCC and CLL is rather rare and in published cases, no cytogenetic examinations were performed. We examined the RB1 gene using the interphase FISH method. A biallelic deletion in CLL tumour cells was detected; in MCC tumour cells, biallelic deletion was found in 33 % of the cells and monoallelic deletion in 57 % of the cells. In addition, chromosome 6 trisomy and 1p36 deletion were detected. Examination of non-neoplastic cells of the patient’s skin showed a biallelic presence of the RB1 gene. According to the relevant literature, examination of the RB1 gene in CLL has informational value as a prognostic factor. The relationship between deletion of the RB1 gene and prognosis in MCC has not yet been determined and needs more research.

• Klíčová slova
• RB1 gen,
• MeSH
• chromozomální delece MeSH
• chronická lymfatická leukemie diagnóza   genetika   komplikace   MeSH
• elektronová mikroskopie MeSH
• geny retinoblastomu MeSH
• hybridizace in situ fluorescenční MeSH
• imunohistochemie metody   využití   MeSH
• komorbidita MeSH
• lidé středního věku MeSH
• lidé MeSH
• Merkelův nádor diagnóza   genetika   komplikace   MeSH
• retinoblastomový protein genetika   izolace a purifikace   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

• MeSH
• exprese genu MeSH
• nádory jater genetika   MeSH
• retinoblastomový protein genetika   MeSH
• virus hepatitidy B MeSH

• MeSH
• buněčné jádro chemie   MeSH
• finanční podpora výzkumu jako téma MeSH
• geny abl genetika   MeSH
• lidé MeSH
• protoonkogenní proteiny c-myc genetika   MeSH
• retinoblastomový protein genetika   MeSH
• Check Tag
• lidé MeSH

In our routine and consultative pathology practices, we have noticed that a relatively high proportion of spindle cell predominant trichodiscomas demonstrate a remarkable stromal admixture of adipose tissue, which along with spindle cells, prominent collagen bundles and myxoid change closely resembles spindle cell lipoma (SCL). To clarify their possible relationship to SCL, 25 cases of trichodiscoma and fibrofolliculoma with stromal "lipomatous metaplasia" were collected and examined using immunohistochemical stains [CD34 and retinoblastoma-1 (RB1) protein] and fluorescence in situ hybridization (RB1 deletion). The patients ranged in age from 35 to 81 years (median 64 years). The male to female ratio was almost equal (14:11). All tumors with a known location were situated on the face with a special predilection for the nose. All cases were sporadic, with all patients having a single lesion and showing no clinical features of Birt-Hogg-Dubé syndrome. No case with available follow-up presented with a recurrence or an otherwise aggressive clinical course. Spindle cell stroma was immunohistochemically positive for CD34 in 16 of 20 cases, and 18 of 19 cases showed loss of RB1 staining in lesional spindle cells. Fluorescence in situ hybridization analysis detected RB1 gene heterozygous deletion in 6 of 20 cases. We conclude that despite the SCL-like appearance of the investigated cases, the majority of them supposedly represent genuine spindle cell predominant trichodiscomas with adipose tissue admixture. However, there was a subset of histopathologically indistinguishable cases with proved RB1 deletion, which likely represent SCL with trichodiscoma/fibrofolliculoma-like epithelial/adnexal induction rather than spindle cell predominant variant of trichodiscoma.

• MeSH
• buňky stromatu patologie   MeSH
• databáze faktografické MeSH
• delece genu * MeSH
• diferenciální diagnóza MeSH
• dospělí MeSH
• heterozygot MeSH
• hodnocení rizik MeSH
• hybridizace in situ fluorescenční MeSH
• imunohistochemie MeSH
• jehlová biopsie MeSH
• lidé středního věku MeSH
• lidé MeSH
• lipom genetika   patologie   MeSH
• nádory kůže genetika   patologie   MeSH
• retrospektivní studie MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• sexuální faktory MeSH
• věkové faktory MeSH
• vřetenobuněčný névus genetika   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Mantle cell lymphoma (MCL) is a chronically relapsing malignancy with deregulated cell cycle progression. We analyzed efficacy, mode of action, and predictive markers of susceptibility to palbociclib, an approved CDK 4/6 inhibitor, and its combination with venetoclax, a BCL2 inhibitor. METHODS: A panel of nine MCL cell lines were used for in vitro experiments. Four patient derived xenografts (PDX) obtained from patients with chemotherapy and ibrutinib-refractory MCL were used for in vivo proof-of-concept studies. Changes of the mitochondrial membrane potential, energy-metabolic pathways, AKT activity, and pro-apoptotic priming of MCL cells were evaluated by JC-1 staining, Seahorse XF analyser, genetically encoded fluorescent AKT reporter, and BH3 profiling, respectively. MCL clones with gene knockout or transgenic (over)expression of CDKN2A, MYC, CDK4, and RB1 were used to estimate impact of these aberrations on sensitivity to palbociclib, and venetoclax. RESULTS: Co-targeting MCL cells with palbociclib and venetoclax induced cytotoxic synergy in vitro and in vivo. Molecular mechanisms responsible for the observed synthetic lethality comprised palbociclib-mediated downregulation of anti-apoptotic MCL1, increased levels of proapoptotic BIM bound on both BCL2, and BCL-XL and increased pro-apoptotic priming of MCL cells mediated by BCL2-independent mechanisms, predominantly palbociclib-triggered metabolic and mitochondrial stress. Loss of RB1 resulted in palbociclib resistance, while deletion of CDKN2A or overexpression of CDK4, and MYC genes did not change sensitivity to palbociclib. CONCLUSIONS: Our data strongly support investigation of the chemotherapy-free palbociclib and venetoclax combination as an innovative treatment strategy for post-ibrutinib MCL patients without RB1 deletion.

• Publikační typ
• dopisy MeSH

Little is known of the molecular mechanisms underlying the differentiation of the melanocyte from the melanoblast or the progression from the melanocyte to a malignant melanoma. Since the adenovirus E1A products have proved a useful tool for understanding control of differentiation in other systems, we explored the possibility of using E1A as a probe for factors controlling melanocyte-specific gene expression and differentiation. The results obtained show that the adenovirus E1A 13S, but not the 12S, product can transform the highly pigmented and TPA-dependent melanocyte cell line melan-a. Transformation is characterised by a morphological change, loss of TPA-dependence, the ability to grow in soft agar and strikingly, loss of pigmentation which correlates with loss of expression of the melanocyte-specific TRP-1 and tyrosinase genes. Cotransfection assays demonstrated that repression of TRP-1 by E1A correlated with E1A binding to p105Rb and p300, with the target in the TRP-1 promoter being the M-box, and 11 bp basic-Helix-loop-Helix (bHLH) factor-binding motif conserved between melanocyte-specific promoters. Consistent with the M-box acting as a target for E1a-mediated transcription repression, we also show that the basic-helix-loop-helix-leucine zipper (bHLH-LZ) protein (Mi) encoded by the microphthalmia gene (mi), which is required for pigment cell differentiation, is a positive acting transcription factor which can interact with the retinoblastoma product in vitro and activate the TRP-1 promoter. Moreover, expression of the mi gene was reduced around 50-fold in the non-pigmented E1a-transformed melan-a cells compared to the nontransformed melan-a cell line, with ectopic expression of Mi able to prevent repression of the tyrosinase and TRP-1 promoters in the presence of E1A. Mi therefore appears to play a crucial role in melanocyte-specific gene expression. The parallels between repression of myogenesis and muscle cell bHLH factors, and Mi and melanocyte differentiation are discussed.

• MeSH
• adenovirové proteiny E1A * metabolismus   MeSH
• buněčná diferenciace MeSH
• buněčné linie MeSH
• DNA primery MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• down regulace MeSH
• genetická transkripce MeSH
• jaderné proteiny metabolismus   MeSH
• melanocyty enzymologie   metabolismus   MeSH
• membránové glykoproteiny * MeSH
• molekulární sekvence - údaje MeSH
• myši MeSH
• oxidoreduktasy * MeSH
• protein p300 asociovaný s E1A MeSH
• proteiny genetika   MeSH
• regulace genové exprese * MeSH
• retinoblastomový protein genetika   metabolismus   MeSH
• sekvence nukleotidů MeSH
• trans-aktivátory * MeSH
• transkripční faktor spojený s mikroftalmií MeSH
• transkripční faktory metabolismus   MeSH
• tyrosinasa genetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Superficial acral fibromyxoma (SAF) is an uncommon benign dermal mesenchymal lesion of adults with predilection for acral sites, in particular the nail region. To date, less than 300 cases have been reported. SAFs consistently express CD34, but other diagnostic markers or specific genetic alterations have not been established yet. We describe 11 SAFs occurring in 7 men and 4 women aged 37 to 86years (median, 48 years). Mean size was 6mm (range, 4-20mm). Affected sites were fingers (n=5), toes (n=3), heel (n=1), calf (n=1), and unspecified digit (n=1). None of 10 patients with available follow-up (2-60months; median, 24months) developed recurrence. Histology showed relatively hypocellular vaguely lobulated nodules composed of bland-looking spindled or stellate fibroblast-like cells arranged into storiform or loose fascicles within a variably myxoid, fibromyxoid, or collagenous vascularized stroma. Immunohistochemistry showed expression of CD34 (9/10) and focal weak reactivity for epithelial membrane antigen (2/11). None of the lesions expressed protein S100 (0/11), MUC4 (0/11), or STAT6 (0/11). Loss of Rb1 immunoexpression was observed in 9 (90%) of 10 cases. All 7 cases with successful RB1 fluorescence in situ hybridization testing showed RB1 gene deletions, which was variably associated with co-loss of the corresponding 13q12 signal (monosomy at the 13q region). To our knowledge, this is the first study investigating the expression status of the tumor suppressor Rb1 in SAF by immunohistochemistry and fluorescence in situ hybridization. Our results showed frequent Rb1 deficiency as a possible driver molecular event in SAF (seen in 90% of cases) indicating relationship of SAF to the RB1-deleted tumor family.

• MeSH
• biopsie MeSH
• delece genu * MeSH
• dospělí MeSH
• fenotyp MeSH
• fibrom chemie   diagnóza   genetika   patologie   chirurgie   MeSH
• genetická predispozice k nemoci MeSH
• hybridizace in situ fluorescenční * MeSH
• imunohistochemie * MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery analýza   genetika   MeSH
• nádory kůže chemie   diagnóza   genetika   patologie   chirurgie   MeSH
• prediktivní hodnota testů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• tumor burden MeSH
• ubikvitinligasy analýza   genetika   MeSH
• vazebné proteiny retinoblastomu analýza   genetika   MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The retinoblastoma gene product (pRB) participates in the regulation of the cell division cycle through complex formation with numerous cellular regulatory proteins including the potentially oncogenic cyclin D1. Extending the current view of the emerging functional interplay between pRB and D-type cyclins, we now report that cyclin D1 expression is positively regulated by pRB. Cyclin D1 mRNA and protein is specifically downregulated in cells expressing SV40 large T antigen, adenovirus E1A, and papillomavirus E7/E6 oncogene products and this effect requires intact RB-binding, CR2 domain of E1A. Exceptionally low expression of cyclin D1 is also seen in genetically RB-deficient cell lines, in which ectopically expressed wild-type pRB results in specific induction of this G1 cyclin. At the functional level, antibody-mediated cyclin D1 knockout experiments demonstrate that the cyclin D1 protein, normally required for G1 progression, is dispensable for passage through the cell cycle in cell lines whose pRB is inactivated through complex formation with T antigen, E1A, or E7 oncoproteins as well as in cells which have suffered loss-of-function mutations of the RB gene. The requirement for cyclin D1 function is not regained upon experimental elevation of cyclin D1 expression in cells with mutant RB, while reintroduction of wild-type RB into RB-deficient cells leads to restoration of the cyclin D1 checkpoint. These results strongly suggest that pRB serves as a major target of cyclin D1 whose cell cycle regulatory function becomes dispensable in cells lacking functional RB. Based on available data including this study, we propose a model for an autoregulatory feedback loop mechanism that regulates both the expression of the cyclin D1 gene and the activity of pRB, thereby contributing to a G1 phase checkpoint control in cycling mammalian cells.

• MeSH
• adenovirové proteiny E1A * fyziologie   MeSH
• antigeny transformující polyomavirové * fyziologie   MeSH
• buněčné linie MeSH
• buněčný cyklus * MeSH
• cyklin D1 MeSH
• cykliny fyziologie   metabolismus   MeSH
• lidé MeSH
• lidské adenoviry genetika   MeSH
• onkogenní proteiny virové * fyziologie   MeSH
• onkogenní proteiny * fyziologie   MeSH
• onkogeny * MeSH
• opičí virus SV40 genetika   MeSH
• Papillomaviridae genetika   MeSH
• regulace exprese virových genů MeSH
• retinoblastomový protein * fyziologie   MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH

Jumonji (JMJ, Jarid2), a prototypical member of the jumonji domain-containing protein family, plays a major role in embryonic cardiac development, but its role in the developed heart is unclear. Cardiomyocytes from neonatal mouse heart were treated in culture with NO donor SIN-1, 500 microM, for 2, 4, and 20 h. SIN-1 treatment was associated with a significant and 6.9 +/- 2.5 fold increase in jmj gene expression over all time points. The expression of jmj increased markedly and significantly 4.2 +/- 1.1 fold, 16.6 +/- 4.1 fold, and 2.7 +/- 0.3 fold, respectively, at time points 2 h, 4 h, and 20 h after treatment. The ability of the increase in gene expression to translate into an increase in cellular protein expression was ascertained by Western blotting, which showed an increase in the JMJ protein in whole-cell lysates. Because of the relationship of JMJ to Rb and ANP in the heart, gene expression of these proteins was also examined. SIN-1 produced a small but significant increase in Rb2, but not Rb1 or Rb-binding proteins 4, 6, or 7. In contrast, SIN-1 produced a marked and significant reduction in natriuretic peptide precursor type B but not type C to 0.24 +/- 0.09 fold of the control. These data suggest that JMJ may be a critical, previously unrecognized factor that mediates some of the cellular effects of NO, that NO may be able to increase JMJ in diseases associated with reduced JMJ expression.

• MeSH
• donory oxidu dusnatého farmakologie   MeSH
• kardiomyocyty metabolismus   účinky léků   MeSH
• kultivované buňky MeSH
• molsidomin analogy a deriváty   farmakologie   MeSH
• myši MeSH
• natriuretický peptid typu B genetika   metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• protein p130 podobný retinoblastomu genetika   MeSH
• proteiny nervové tkáně genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• srdce MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH

To elucidate the regulator-versus-target relationship in the cyclin D1/cdk4/retinoblastoma protein (pRB) pathway, we examined fibroblasts from RB-1 gene-deficient and RB-1 wild-type littermate mouse embryos (ME) and in human tumor cell lines that differed in the status of the RB-1 gene. The RB+/+ and RB-/- ME fibroblasts expressed similar protein levels of D-type cyclins, cdk4, and cdk6, showed analogous spectra and abundance of cellular proteins complexed with cdk4 and/or cyclins D1 and D2, and exhibited comparable associated kinase activities. Of the two human cell lines established from the same sarcoma biopsy, the RB-positive SKUT1B cells contained cdk4 that was mainly associated with D-type cyclins, contrary to a predominant cdk4-p16INK4 complex in the RB-deficient SKUT1A cells. Antibody-mediated neutralization of cyclin D1 arrested the RB-positive ME and SKUT1B cells in G1, whereas this cyclin appeared dispensable in the RB-deficient ME and SKUT1A cells. Lack of requirement for cyclin D1 therefore correlated with absence of functional pRB, regardless of whether active cyclin D1/cdk4 holoenzyme was present in the cells under study. Consistent with a potential role of cyclin D/cdk4 in phosphorylation of pRB, monoclonal anti-cyclin D1 antibodies supporting the associated kinase activity failed to significantly affect proliferation of RB-positive cells, whereas the antibody DCS-6, unable to coprecipitate cdk4, efficiently inhibited G1 progression and prevented pRB phosphorylation in vivo. These data provide evidence for an upstream control function of cyclin D1/cdk4, and a downstream role for pRB, in the order of events regulating transition through late G1 phase of the mammalian cell division cycle.

• MeSH
• cyklin D1 MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasy * MeSH
• cykliny antagonisté a inhibitory   imunologie   metabolismus   MeSH
• DNA primery genetika   MeSH
• fosforylace MeSH
• G1 fáze * fyziologie   genetika   MeSH
• geny retinoblastomu * MeSH
• kultivované buňky MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• myši knockoutované MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• neutralizační testy MeSH
• onkogenní proteiny antagonisté a inhibitory   imunologie   metabolismus   MeSH
• protein-serin-threoninkinasy * metabolismus   MeSH
• protoonkogenní proteiny * MeSH
• retinoblastomový protein genetika   metabolismus   MeSH
• sekvence nukleotidů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH